The following background information is provided to assist the reader to understand the environment in which the invention will typically be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless specifically stated otherwise in this document.
The problems with discharging effluent matter, such as grease, through roof mounted exhaust fan systems are well known in the field of commercial food preparation and commercial heating, ventilating and air conditioning systems. The grease used in commercial food preparation as well as other products of combustion accumulates in the exhaust stack and is discharged into the atmosphere through roof top mounted exhaust fans. The discharge corrodes and degrades the roof surface and poses a fire hazard as the grease may ignite. The restoration of the roof surface is an expensive and time consuming effort.
To mitigate the grease discharge problems, grease containment and filter systems have been employed to collect the discharged grease.
U.S. Pat. No. 6,391,074 to McCrary and U.S. Pat. No. 6,143,047 to Jodoin et al. teach roof mounted containment assemblies that surround the exhaust fan and employ replaceable filter elements to collect the grease discharge. However, these systems are expensive to install and enable exposure of the grease discharge to the environment.
U.S. Pat. No. 5,814,115 to Allen et al. teaches, in one aspect, a grease filter system for use with a bottom discharge exhaust fan that includes a receptacle and a filter element removably supported within the receptacle. The receptacle further includes a lid with an opening through which grease, condensed steam, water and other products of combustion can enter the system. A dispersion tray is disposed below the lid for guiding the discharged grease into the receptacle. A plurality of apertures is provided at the bottom portion of the receptacle to retain grease and other viscous fluids while allowing condensed steam, water and other products of combustion to pass through the filter element and exit the receptacle through the apertures.
While offering improved grease containment, the system is roof mounted and requires careful handling of the filter element during replacement effort so as not to incur spillage. Furthermore, the inclusion of the dispersion tray increases the installation costs.
In another aspect, U.S. Pat. No. 5,814,115 to Allen et al. teaches a filter system for use with a side discharge exhaust fan that includes a receptacle secured to the side of the duct housing connected to the exhaust fan housing. A filter element is removably disposed within the receptacle and a lid with a narrow opening, which is aligned with the side drain spout, is provided for receiving the discharged grease and other effluent matter. A dispersion tray is disposed below the lid for guiding it into the filter element.
It has been found that such system, when not aligned properly, enables discharged grease to spill onto the roof surface.
Additionally, it is well known that air ventilating exhaust fans accumulate grease and other effluent matter on the interior wall surface of the fan housing and such grease is being discharged onto the roof by rain water.
Therefore, it is desirable to provide an effluent filtering and containment apparatus that improves containment of the grease and other effluent discharge, reduces installation costs and minimizes difficulties with handling saturated filter elements during replacement effort.